Saudi Arabia's new crown prince earned the nickname "The Prince of Shadows" during a 36-year counter-terror career in which he thwarted al Qaeda's ambitions inside the Kingdom and may also have survived assassination attempts by radical Islamists.

Prince Nayef bin Abdul Aziz became known as "The Prince of Shadows," said former U.S. ambassador Charles Freeman, because he was in charge of Saudi Arabia's secret police, and because of his night owl schedule, holding meetings long after midnight.

The man who is now next in line to become Saudi Arabia's king is widely credited with steering Saudi Arabia back to relative security and stability after an upsurge in terror between 2003 and 2006. "He has overseen an incredibly successful counter-terrorism strategy," said a U.S. official familiar with security in Saudi Arabia, who credits Prince Nayef with effectively driving Al Qaeda in the Arabian Peninsula (AQAP), the terror group's local affiliate, out of the Kingdom.

Nayef, 78, has been the Kingdom's interior minister since 1975, overseeing internal security, and according to a 2009 U.S. State Department cable leaked by WikiLeaks, his world view is framed by U.S./Saudi cooperation, the threat from Iran, and thwarting terrorism inside Saudi Arabia. The cable describes him as "a conservative pragmatist" who will "continue security and other forms of cooperation [with the U.S.], but possibly prove more resistant than the current leadership on human rights issues."

After a string of high profile terrorist attacks including the beheading of Paul Johnson, an American citizen in Riyadh and an attack on the U.S. consulate in Jeddah in 2004, the Kingdom's security forces, under the helm of Nayef have been able to thwart comparable operations over the past 5 years. Killing or capturing high level AQAP operatives among whom the terrorist organization's first operational leader, they were also able to foil in 2006 an AQAP attack on the Abqaiq oil installation, the largest in the Kingdom.

There may also have been several attempts on Nayef's life, though a U.S. official said it is unclear whether the incidents, which involved shots fired at his residence and at his convoy of vehicles, constitute full-fledged assassination tries.

Nayef's son Prince Muhammad bin Nayef, however, has been the target of multiple assassination attempts. Muhammad, a deputy interior minister, survived a bombing in August 2009 in which a man with a bomb apparently hidden in a body cavity detonated the device close to him.

The bomb was allegedly designed by AQAP bombmaker Ibrahim al-Asiri, the same Saudi expatriate who designed the underwear bomb used by Umar Farouk Abdulmutallab in his attempt to bring down Northwest flight 253 over Detroit on Christmas 2009. The bomber, who died in the blast, was al-Asiri's brother Abdullah. Prince Muhammad survived with minor injuries.

Nayef's appointment as crown prince had raised questions about whether Saudi Arabia's reforms would continue, but after the 2009 attempt on his son Muhammad's life, says the leaked U.S. diplomatic cable, Nayef "noticeably associated himself with reform efforts." The cable quotes him as saying that the "security efforts and reform strategy the country is following will not change."

And though Nayef is a social conservative who is skeptical of the King's gradual efforts to improve women's rights and political participation, it was one of his security-driven initiatives that granted women ID cards and subsequently allowed them to register in universities, independently establish bank accounts and start businesses.

Succession in Saudi Arabia goes from brother to brother instead of from brother to son to minimize family feuds among the 37 sons of Saudi Arabia's founding King Abdul Aziz. Crown Prince Nayef is one of the seven most powerful brothers in the family whose mother was a favorite of the late founding king. The present king, Abdullah bin Abdul-Aziz al Saud, is 87 years old and has been king since 2005.